A wave of localised koala extinction has been sweeping across state's far west and coastal populations have been decimated by the bushfires, leaving the region's koalas as one of the few unaffected populations.

Concerns have once again been raised about Shenhua's proposal to relocate the koalas from its proposed mine site on the Liverpool Plains, experts pointing to the high mortality rate of translocation.

Caroona Coal Action Group president Susan Lyle said the Shenhua coal mine's threat to koalas was often reduced to a side issue, but it should take centre stage.

"The bottom line is: do we want koalas or not?" Ms Lyle said.

"If we do, let's step up. We are in an area where they are still surviving - they're drought-affected, but they're still here. That's the very reason they must be protected."

A number of independent experts on the company's Koala Technical Working Group have raised issues with the prospect of moving koalas, noting translocation should be "the last resort with minimum numbers and preferably none, as the risk of koala deaths is high".

As part of Shenhua's interim koala habitat plan, the company planted 2500 trees at the end of last year, to create a tree corridor for koalas.

Ms Lyle said the trees were currently only six inches high and would struggle to survive the drought.

"That doesn't pass any sort of pub test; they're just ticking a box," Ms Lyle said.

"If they were really concerned about koalas, they should've planted trees five years ago.

"These trees are going to take ages to reach a stage of maturity where they'll be able to support koalas."

Shenhua documents concede the "conditions are difficult at present due to the drought", but go on to say "the trees will be monitored".

Both NSW Labor and NSW Greens have called for the state government to take immediate action to protect the state's remaining koala population.

Koalas are currently classified as "vulnerable", but Federal Environment Minister Sussan Ley said some populations that had been affected by the bushfires could be reclassified as "endangered".